Hello and welcome to FF Jennifer! In the 18 in. cube can keep 2 (it's around 24 gallons) and in the 24 in. tall can keep 3. If the Melanistic is smaller an it fits in other frogs mouth it could be eaten. Also, it could grab less than it's fare share of crickets or just be stressed to point it's health declines.

Your frog has great colors and those are nice pics too; should enter forum's monthly photo contest .